Fc (Unix)

fc
Developers	Various open-source and commercial developers
Operating system	Unix, Unix-like
Platform	Cross-platform
Type	Command

fc (short for fix command ^[1] ) is a shell command that lists, edits and re-executes commands previously entered in the shell. It is particularly helpful for editing complex, multi-line commands. Originally developed for Unix and standardized by POSIX, the command is available in many operating systems today.

As it is required to be "intrinsic" by POSIX, ^[2] it is implemented as a builtin in the Bash, Zsh, and Almquist shells.

Invoked with no options, the command opens a text editor, allowing the user to modify the last-run command. Upon exiting the editor, the modified command is executed in the current shell. ^[3] The editor used can be specified with the -e option; otherwise it is read from the FCEDIT environment variable, ^[4] or, in some shells, EDITOR, ^{[5] [6] [7]} with a fallback to vi or ed. Command-line options allow for quick substitution, repetition or modification of a specific command from the session history, or a range of commands from the history.

Examples

When invoked with the -l option, the command lists recent lines from the session history:

$ fc-l 1  pwd2  whoami3  ls4    ls -a

When invoked with -s PATTERN, the command re-runs the most recent command matching PATTERN:

$ fc-sls ls -a.  ..  .bash_logout  .bashrc  .profile

Option -s enables inline substitution. For example, consider that the last command ls floder contains a typo. The following command runs the last command with "flod" replaced with "fold":

$ fc-sflod=fold ls folder

It is also possible to edit and re-invoke a range of commands from the history. Often, one lists commands first like:

$ fc-l 1  pwd2  whoami3  ls4    ls -a5    ls -la

Then, to run the commands identified as 1 and 2:

$ fc12pwd/home/userwhoamiuser

External links

• fc : process the command history list – Shell and Utilities Reference, The Single UNIX Specification , Version 5 from The Open Group

See also

• List of POSIX commands

References

1. "IEEE Std 1003.1-2024 - fc § Rationale". pubs.opengroup.org. Retrieved 2025-04-22.
2. "The Open Group Base Specifications Issue 8 (IEEE Std 1003.1-2024) - fc § Application Usage". pubs.opengroup.org. Retrieved 2025-04-22.
3. "Fix history: Edit the last bash command". 5 January 2020.
4. "IEEE Std 1003.1-2024 - fc § Environment Variables". pubs.opengroup.org. Retrieved 2025-04-22.
5. "Bash History Builtins (Bash Reference Manual)". www.gnu.org. Retrieved 2025-04-22.
6. "The Z Shell Manual § 15.6 Parameters Used By The Shell". zsh.sourceforge.io. Retrieved 2025-04-22.
7. "dash FreeBSD manual page § "Builtins"". man.freebsd.org. Retrieved 2025-04-22.